Shopify /buy links: what changes from cart permalinks

Shopify has added a /buy route for cart and checkout links, using the Universal Commerce Protocol. Announced on 28 October 2026, it lets an app or agent hand a shopper a link containing products, quantities and supported checkout details.

Existing /cart links continue working. Shopify says future capabilities will go to the new format, so this is a migration to evaluate when building new campaigns rather than an emergency replacement of every live link.

Choose the format around the offer

The compatibility table is particularly useful for personalised products. The new format does not yet carry line-item properties, cart notes, cart attributes or sales-channel attribution. Keep legacy links where those supported features are essential.

Subscriptions need separate attention: Shopify’s current comparison table and legacy guide say selling plans are supported by neither format. Although the release announcement groups selling plans with reasons to retain legacy links, that wording should not be read as a working subscription solution. Check the subscription provider’s documented purchase flow.

Build from the store’s published endpoint

Shopify’s implementation guide instructs builders to read the permalink endpoint from the store’s UCP discovery profile. Supported parameters include discount codes, country, language and a Shop Pay preference. Buyer details belong only in private links sent to that buyer, not public campaigns.

For a BFCM campaign, our recommendation is to test the actual offer link on desktop and mobile before it goes into an email or QR code. Check quantities, the discount, destination and what happens when a variant sells out. Test with an existing cart as well: replacing it may surprise a returning shopper.

Separate the handoff from payment approval. Our earlier guide to UCP buyer consent covers another part of agent checkout; a link opening successfully is not proof that every downstream preference is handled.